title: Validation of cardiac output using real-time measurement of oxygen consumption during cardiac catheterization in children under 3 years of age.
abstract: OBJECTIVE
  To validate a method for determination of cardiac index (CI) using real-time measurement of oxygen consumption (VO2 ) in young children undergoing cardiac catheterization.
  
  
  METHODS
  Retrospective review comparing thermodilution cardiac index (TDCI) to CI calculated by the Fick equation using real-time measured VO2 (RT-VO2 ) and VO2 derived from 2 published predictive equations. Paired t-test and Bland-Altman analysis were used to compare TDCI to Fick CI. A survey to ascertain pediatric cardiac catheterization practices regarding VO2 determination was also conducted.
  
  
  METHODS
  Quaternary care children's hospital cardiac catheterization laboratory.
  
  
  METHODS
  Children <3 years old with structurally normal hearts undergoing cardiac catheterization under general anesthesia with at least one set of contemporaneous TDCI and RT-VO2 measurements.
  
  
  RESULTS
  Thirty-six paired measurements of TDCI and RT-VO2 were made in 27 patients over a 2-year period. Indications for catheterization included congenital diaphragmatic hernia postrepair (n = 13), heart disease post-orthotopic heart transplant (n = 13), and suspected cardiomyopathy (n = 1). Mean age was 21.5 ± 8 months; median weight was 9.9 kg (IQR 8.57, 12.2). RT-VO2 was higher than VO2 predicted by the LaFarge equation (190 ± 31 vs. 173.8 ± 12.8 mL/min/m(2), P < .001), but there was no difference between TDCI and Fick CI calculated using VO2 from any method. Bland-Altman analysis showed excellent agreement between TDCI and Fick CI using RT-VO2 and VO2 predicted by the Lundell equation; Fick CI using VO2 predicted by the LaFarge equation showed fair agreement with TDCI.
  
  
  CONCLUSIONS
  In children <3 years with a structurally normal heart, RT-VO2 generates highly accurate determinations of Fick CI as compared with TDCI. Additionally, in this population, VO2 derived from the LaFarge and Lundell equations generates accurate Fick CI compared with TDCI. Future studies are needed to identify factors associated with inaccurate VO2 generated from these predictive equations.
authors.affiliation: The Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Seckeler
authors.forename: Russel
authors.initials: R
authors.lastname: Hirsch
authors.forename: Robert H
authors.initials: RH
authors.lastname: Beekman
authors.forename: Bryan H
authors.initials: BH
authors.lastname: Goldstein
mesh_terms: D000367:Age Factors; D001944:Breath Tests; D006328:Cardiac Catheterization; D002302:Cardiac Output; D002675:Child, Preschool; D005260:Female; D019538:Health Care Surveys; D006776:Hospitals, Pediatric; D006801:Humans; D007223:Infant; D008297:Male; D008955:Models, Cardiovascular; D010101:Oxygen Consumption; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012189:Retrospective Studies; D011795:Surveys and Questionnaires; D013815:Thermodilution; D013997:Time Factors
keywords: Cardiac Catheterization; Cardiac Output; Hemodynamics; Oxygen Consumption; Pediatric Cardiology